Flame cultivator



Sept. 26, 1950 v. A. JOHNSON 2,523,953

7 FLAME CULTIVATOR Filed June 29, 1946 r 3 Sheets-Sheet 1 Sept. 26, 1950 I v. A. JOHNSON 2,523,953

FLAME CULTIVATOR Filed June 29, 19 46 3 Shets-Sheet 2 P 1950 v. A. JOHNSON 2,523,953

FLAME CULTIVATOR Filed June 29, 1946 I 3 Sheets-Sheet s 2 f 30 l 30 2,9 23 30 I" J Patented Sept. 26, 1950 Application June 29, 1946, Serial No. 680,393

7 Claims.

My invention relates to flame cultivators of the type comprisin a vehicle with means transported thereby for killing vegetation by the application of intense heat. The invention is directed particularly to the construction of a flame cultivator for utilizing liquefied gaseous fuel.

In an apparatus of this type a supply of liquefied fuel, such as butane or propane, is provided in a suitable tank under pressure, and is released from the tank for vaporizatio and expansion in preparation for combustion. One problem encountered in the operationof such an apparatus is the excessive refrigeration effect resulting from the vaporization and. expansion of the fuel. The freezing action interferes with the functioning of the system, and, in the absence of suitable remedial measures, will prevent continuous operation of the system for any substantial period of time. One object of my invention is to solve this problem by applying heat to the fuel in compensation for the heat of vaporization and expansion.

Intense heat is required for killing undesirable vegetation along a row in a field under cultivation, and the apparatus is normally operated with relatively ho-t flames. Frequently, however, it is desirable to cut down the hot flames temporarily to avoid unwanted burning action. When the apparatus reaches the end of a row, for example, and is maneuvered to enter another row, it is desirable to reduce the flames to a minimum with- I out stopping combustion.

Another object of the invention is to provide an apparatus of the present character having a quick acting control for this purpose of reducing the fuel combustion to a desirably low rate at the election of the operator. One difficulty to be surmounted is to keep the above mentioned compensating heating means in proper balance with the reduced rate of fuel consumption when the fuel system is throttled down, as at the end of a row. A feature of my invention is the manner in which such balance or correlation is accomplished.

In general these objects are attained by employing a combustion system with a high pressure fuel passage for normally high rate combustion, an alternate low pressure fuel passage for combustio-n at a reduced rate, and a quick-acting valve controlling the high pressure passage. Both of the passages are adapted to deliver fuel to the compensating heater as well as to the combustion means for generating the vegetation-destroying flames. When the quick-acting valve is open, fuel under high pressure is supplied at a relatively rapid rate both to the compensating heater and to the combustion means, but when the quick-acting valve is closed fuel at only low pressure is supplied.

Other objects and advantages of my invention will be apparent in the following detailed description taken with the accompanying drawings.

In the drawings, which are to be considered as merely illustrative:

Fig. 1 is a side elevation of the preferred embodiment of my invention, attached toa tractor;

Fig. 2 is an elevation of the apparatus as viewed from the rear;

Fig. 3 is a diagrammatic view of the essential parts of the combustion system as viewed in plan; and

Fig. 4 is a similar diagrammatic View in side elevation.

Fig. 1 illustrates how the invention may be embodied in an apparatus adapted to be hitched to a tractor, generally designated ill, for the cultivation of field crops. The apparatus includes a suitable frame, generally designated l i, that is adapted in any well known manner f01' releasable attachment to the tractor. Preferably the frame II is of articulated construction, being provided with a hinge [2 to permit the frame to be swung up or down relative to the tractor.

The frame l I includes two spaced cross-bars i3, [4, on which are mounted a plurality of curved downwardly extending arms 15 to carry a corresponding plurality of ground-working members I6 for mechanical cultivation of the soil. In the particular construction shown the ground-working members I6 are of a well known type, with blades to penetrate the soil. The ground-work ing members are adjustable to various angles, being for this purpose mounted on pivots l I (Fig. 1) and releasably fixed by suitable bolts i8 extending through slots 20.

Also mounted on the forward cross-bar i3 are a number of downwardly extendin arms 2! to carry corresponding main burners or combustion means 22. Each of the combustion means 22 is shown adjustably pivoted on a bracket 23, and each of the brackets 23 is in turn mounted on the corresponding arm 2! in a vertically adjustable manner. In the particular construction shown. each bracket 23 has a plurality of holes 24 for use selectively in securing the bracket to the arm by bolts 25.

While any number of combustion means or burners 22 may be employed, four are shown on the particular apparatus chosen for illustration. The four burners are arranged in two pairs, with the two burners of each pair directed toward each other, as best shown in Fig. 2, so that flames may be directed toward plants 26 from opposite sides.

' Each of the f our burners 22 is supplied with vaporized fuel through a downwardly extending flexible conduit or hose 21, the upper end of each hose being connected to a nipple 26 controlled by an individual valve 36. The four nipples 28 branch from a pipe or manifold 3 i.

The fuel system for supplying vaporized fuel to the four burners 22 includes a cylindrical fuel tank 32 for holding liquefied gaseous fuel under pressure. This tank may be supported on the frame H by a pair of suitable brackets 33. Each of the brackets 33 includes a split girth band 35, which is normally closed by bolts 36 but may be opened when it is desired to substitute one fuel tank for another.

The construction and arrangement of the system for supplying vaporized fuel to the four burners 22 in the preferred practice of my invention may best be understood by referring to the diagram of Figs. 3 and 4. The fuel tank 32 is provided with the usual valve 3? through which fuel is released from the tank to a pipe 38 leading to a primary pressure-reducing valve or pressure regulator ill. The pressure-reducing valve is shown provided with a pressure gauge 4!, and may be adjusted to release fuel at a suitable pressure. In an initial practice of the invention the adjustment at this point is in the range of to pounds per square inch.

The fuel under the regulated pressure is conducted by a pipe 32 to the bottom of a vaporizin chamber 63, which vaporizing chamber is part.

of a vaporizer or compensating fuel heater, gen-' erally designated 45. The compensating fuel heater includes a small burner 46 and an open end cylinder 5? to conserve heat and to shield the flame of the small burner against the wind. The vaporizing chamber is may, of course, be spherical or of any suitable shape.

From an upper portion of the vaporizing chamber 43 a pipe ,8 extends to a T connection 56. From one side of the T connection 50 a fuel pipe 5! leads to a quick-acting valve 52, and the valve in turn is connected by a pipe 53 to one end of the previously mentioned fuel manifold 3|. The valve 52 is provided with a suitable handle 55 within convenient reach of the operator, and may be of the gate type to open fully and close with a short throw.

The other side of the T connection is connected by a pipe 56 with a secondary pressurereducing valve or pressure regulator 51, provided with a suitable pressure gauge 58. This second pressure regulator 51 receives fuel at the pressure determined by the first regulator, and reduces the pressure of the fuel to a substantial extent. In the initial practice of my invention the pressure is reduced to the range of one fourth pound to one pound per square inch.

From the secondary pressure regulator 51 fuel flows to a T connection 66, from which connection one pipe 6| leads to the previously mentioned compensating burner 46 and a second pipe e2 leads to the second end of the previously :1-

mentioned fuel manifold 3|. The pipes 61 and 62 connecting the burner 46 with the manifold 35! may be regarded as extensions of the manifold. A suitable valve 63 is provided for independent control of the small burner 46.

The described pipe system shown in Figs. 3 and i is seen to provide two passages for flow of the vaporized fuel, one passage being through the quick-acting valve 52 and the other passage being through the secondary pressure regulator 51. It is apparent that if the valve 52 is open the high pressure will predominate in the manifold 3i, so that the vaporized fuel will be supplied at a relatively high rate not only to the four burners 22 but also to the compensating burner 46. When the quick-acting valve 52 is closed, however, fuel can reach the four burners 22 and the compensating burner 46 only through the secondary regulator 27. Thus the pressure and rate of fuel supply to the compensating burner 46 responds to operation of the valve 7 52 whereby the heat supplied by the compensatfor operation the tank valve 31 is opened and the primary pressure regulator 40 is adjusted for the desired pressure. Since the quick-acting valve 52 is closed, the flow of fuel is now limited by the secondary pressure regulator 51, which regulator may now be adjusted as desired. The small valve 63 is opened to permit lighting of the small compensating burner 46. The four valves 36 may now be opened in succession and the four burners 22 lighted, the rate of combustion at the four burners being relatively low as determined by the secondary pressure regulator 51. At this point the apparatus is ready for operation.

As the apparatus enters a row to cross a field the operator throws the quick-acting valve 52 to full open position, whereupon the vaporized fuel at relatively high pressure is supplied to the four burners 22 and also to the compensating burner 46. At the end of the row the operator closes the quick-acting valve 52 to reduce the rate of combustion in the four burners 22 and to reduce the rate of combustion correspondingly in the compensating burner 46.

The amount of heat supplied by the compensating burner 46 may vary, but preferably will be only slightly more than the heat taken up by the fuel in its vaporization and expansion.

Under some circumstances the vaporizer burner may be shut off during operation of the system. For example, on a hot day it may not be necessary to generate heat to compensate for heat required for vaporization of the fuel. If the vaporizer burner is cut off the described system still functions for the useful purpose of reducing the ground flames when desired.

An important advantage of the controlled-v volved will suggest to those skilled in the art v various changes and substitutions within the scope of my appended claims.

I claim as my invention:

1. In an apparatus of the character described, supply means containing liquefied gaseous fuel, means to release fuel from said supply means for vaporization, a burner to heat the released fuel to compensate at least in part for the cooling effect of vaporization, combustion means to produce a vegetation-destroying flame, a first passage means for conducting the vaporized fuel to both said burner and said combustion means, a second passage means including a pressure reducing means for conducting the vaporized fuel to both said burner and said combustion means, and valve means for selectively deliver ing fuel into the receiving end of either of said passage means.

2. In a cultivator for destroying undesirable vegetation, a tank for liquefied gaseous fuel, means including a supply passage for releasing the liquefied fuel from said tank to form vaporized fuel at a given pressure, a burner to apply heat to said supply passage in compensation at least in part for the heat required for vaporization of the fuel, combustion means to produce a vegetation-destroying flame, a first branch passage from said supply passage for conducting the vaporized fuel to both said burner and said combustion means, a second branch passage from said supply passage for conducting the vaporized fuel to both said burner and said combustion means, said branch passage includa ing a means for lowering the pressure of the vaporized fuel passing therethrough whereby to deliver said fuel at a reduced rate, and valve means for selectively delivering vaporized fuel to said passage means.

3. In an apparatus of the character described, means to supply liquefied gaseous fuel, a vaporizing chamber connected with said supply means, a burner for heating said vaporizing chamber, a combustion means to produce a vegetationdestroying flame, a passageway connecting said vaporizing chamber, said combustion means and said burner, valve means to control said passageway, a second passageway connecting said vaporizing chamber, said combustion means and said burner, said second passageway including means to reduce pressure therein whereby to feed vaporized fuel to said combustion means at reduced pressure, and means including a valve for selectively supplying vaporized fuel at a given pressure to said passageway.

4. In an apparatus of the character described, means providing a supply of liquefied gaseous fuel, a vaporizing chamber connected with said supply means to receive fuel therefrom, a first pressure regulator to regulate the pressure of the fuel flow to said vaporizing chamber, a burner to heat said vaporizing chamber, combustion means to produce a vegetation-destroying flame, means providing a first passage for fuel flow from said vaporizing chamber to said combustion means and burner, means providing a second passage from said vaporizing chamber to said combustion means and burner, a pressure regulator to reduce the pressure in said second passage, and valve means for selectively delivering fuel to either of said passage means.

5. In an apparatus of the character described, supply means containing liquefied gaseous fuel, means to release fuel from said supply means for vaporization, combustion means to produce a vegetation-destroying flame, a, passage means: to feed vaporized fuel to said combustion means, a valve controlling said passage means, a by-- pass around said valve to supply fuel to said. combustion means at a reduced rate when said valve means is closed, and a burner to apply heat to the fuel released from said supply means; to compensate at least in part for the cooling; effect of vaporization of the fuel, said burner being connected with said by-pass and also with. said passage means on the discharge side of said! valve whereby the burner varies in its rate of. heat application in accord with the rate of fuel; flow to said combustion means.

6. In a cultivator for destroying undesirable vegetation, a tank for liquefied gaseous fuel, means including a supply passage to release the liquid fuel from said tank to form vaporizedi fuel, combustion means to produce a vegetation-- destroying flame, a main fuel passage for con-' ducting the vaporized fuel to said combustion. means at a given pressure, a valve for said main passage to permit fuel flow therethrough for normal flame operation when the cultivator moves along a row of vegetation and to cut off? flow therethrough during movement of the cultivator from one row to another, a by-pass around said valve to permit fuel to flow to said. combustion means at a relatively low rate when said valve is closed, and a burner for heating the fuel released from said tank in compensa tion at least in part for the heat required for vaporization of the fuel.

'7. In a cultivator for destroying undesirable vegetation, a tank for fluid fuel under pressure, means including a supply passage to release fuel from said tank, a plurality of burners to produce vegetation-destroying flames, a main fuel passage for conducting fuel to said burners from said passage means at a, relatively high rate, a valve for said main passage to permit fuel flow therethrough for normal flame operation and to out off fuel flow therethrough for low flame operation, a by-pass around said valve to supply fuel to said burners for low flame operation when said valve is closed, and a pressure regulator to maintain at a predetermined magnitude the pressure of the fuel supplied through said by-pass whereby when the burners are ignited successively for initiating operation the rate of fuel flow through the by-pass will increase with the number of burners in operation.

VIVION A. JOHNSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,922,573 Dunkak Aug. 15, 1933 2,008,891 Woods July 23, 1935 2,327,204 McLemore Aug. 17, 1943 OTHER REFERENCES the Weeds, "vol. 145, 

